Compositions comprising 1,1,1,3,3-pentafluorobutane and use of these compositions

ABSTRACT

Compositions comprising 1,1,1,3,3-pentafluorobutane and more than 5% by weight of at least one non-flammable fluoro compound, and use thereof.

[0001] The invention relates to compositions comprising1,1,1,3,3-pentafluorobutane and to their use, for example, as solvents,in particular for drying or degreasing, or as refrigerants.

[0002] International agreements aimed at protecting the stratosphericozone layer require that the use of chlorofluorocarbons (CFCs) andhydrochlorofluorocarbons (HCFCs) be gradually reduced or even stopped.Compounds of this type are used, inter alia, as solvents or asrefrigerants. CFC-113, for example, is used as a solvent for degreasingor cleaning surfaces. More recently, HCFC-141b has been used for theseapplications. The latter compound is also used with surfactants, indrying agents. CFC-11 and HCFC-123 are used, for example, asrefrigerants in turbocompressors.

[0003] It is known practice to use 1,1,1,3,3-pentafluorobutane(HFC-365mfc) as a replacement product which respects the ozone layer inapplications as a solvent. However, the use of1,1,1,3,3-pentafluorobutane requires precautions in order to takeaccount of the flammable nature of the product. It has been proposed touse 1,1,1,3,3-pentafluorobutane in compositions with a specificsurfactant and pentafluoropropanol or tridecafluorooctanol (EP-A 863194). However, these compositions have the drawback of being limited asregards the polarity of the possible mixtures. This limits theircapacity to dissolve surfactants. Furthermore, with pentafluoropropanol,increased solubility in semi-aqueous media should be expected, which isunacceptable for certain applications. The high boiling point of thefluoro alcohols used also leads to an enrichment in HFC-365mfc in thegas phase which makes the vapours flammable. Consequently, thecompositions proposed should not be used in drying machines.

[0004] The invention is directed towards overcoming these problems.

[0005] A subject of the invention is thus compositions comprising1,1,1,3,3-pentafluorobutane (HFC-365mfc) and more than 5% by weight ofat least one non-flammable fluoro compound selected fromperfluorocarbons, hydrofluorocarbons comprising more than 3 carbonatoms, fluoroamines and fluoro ethers.

[0006] It has been found, surprisingly, that the compositions accordingto the invention have good properties as regards their flammability andgood technical properties for a wide range of applications.1,1,1,3,3-Pentafluorobutane has the particular advantage of beingmiscible with non-flammable fluoro compounds and of being compatiblewith additives or solvents usually used in applications such as thosementioned above.

[0007] The expressions “non-flammable fluoro compound” and“non-flammable composition” are intended to denote any compound orcomposition which does not have a determined flash point according toISO standard 1523.

[0008] The non-flammable hydrofluorocarbons (HFCs) and perfluorocarbonsused in the compositions according to the invention can be linear,branched or cyclic and generally contain 4, 5, 6, 7, 8, 9 or 10 carbonatoms. Among the hydrofluorocarbons, those comprising at least 5 carbonatoms are suitable for use. 1,1,1,2,3,4,4,5,5,5-Decafluoropentane(HFC-43-10mee) is particularly preferred. Among the perfluorocarbons,those comprising at least 5 carbon atoms are suitable for use.Perfluoropentane and perfluorohexane are preferred. Perfluoropentane andperfluorohexane are usually used in the form of technical mixtures ofisomers, as sold, for example, by 3M under the respective names PF5050for perfluoropentane and PF5060 for perfluorohexane.

[0009] The non-flammable fluoro ethers and fluoroamines which can beused in the compositions according to the invention can be linear,branched or cyclic and generally contain 3, 4, 5, 6, 7, 8, 9 or 10carbon atoms. Among the fluoro ethers, those comprising at least 4carbon atoms are suitable for use. Perfluorobutyl methyl ether isparticularly preferred. Among the fluoroamines, those comprising atleast 4 carbon atoms are suitable for use. Perfluorotriethylamine isparticularly preferred.

[0010] Generally, the non-flammable fluoro compounds have a boilingpoint at 101.3 kPa of greater than or equal to 15° C. Preferably, theboiling point is greater than or equal to 20° C. Generally, the boilingpoint is less than or equal to 130° C. at 101.3 kPa. Usually, theboiling point is less than or equal to 100° C. Preferably the boilingpoint is less than or equal to 85° C.

[0011] The F/H numerical ratio (number of fluorine atoms in the moleculedivided by the number of hydrogen atoms in the molecule) of thenon-flammable fluoro compounds is greater than 2. An F/H numerical ratioof greater than or equal to 2.5 is suitable. Preferably, the F/Hnumerical ratio is greater than or equal to 3.

[0012] The amount of non-flammable fluoro compounds is greater than 5%by weight relative to the mixture consisting of1,1,1,3,3-pentafluorobutane and non-flammable fluoro compounds. Usually,an amount of greater than or equal to 10% by weight is used. An amountof greater than or equal to 20% by weight is preferred. An amount ofgreater than or equal to 25% by weight is suitable for use. An amount ofgreater than or equal to 30% by weight gives good results. In aparticularly preferred manner, the effective amount of non-flammablefluoro compound used is that which makes the composition non-flammable,i.e. the composition has no determined flash point according to ISOstandard 1523. Generally, the amount of non-flammable fluoro compoundsin the compositions according to the invention is not more than 90% byweight.

[0013] Preferred compositions according to the invention comprise, asnon-flammable compound, at least perfluoropentane, perfluorohexane,perfluorobutyl methyl ether or a mixture thereof. A preferred variant ofthe compositions according to the invention relates to compositionscomprising 1,1,1,3,3-pentafluorobutane and at least one perfluorocarbonin proportions in which they form an azeotrope or a pseudo-azeotrope.

[0014] Basically, the thermodynamic state of a fluid is defined by fourinter-dependent variables: the pressure (P), the temperature (T), thecomposition of the liquid phase (X) and the composition of the gas phase(Y). A true azeotrope is a specific system of 2 or more components forwhich, at a given temperature and a given pressure, the composition ofthe liquid phase X is exactly equal to the composition of the gas phaseY. A pseudo-azeotrope is a system of 2 or more components for which, ata given temperature and a given pressure, X is substantially equal to Y.In practice, this means that the constituents of such azeotropic andpseudo-azeotropic systems cannot be readily separated by distillationand consequently there is no enrichment in flammable compound in the gasphase.

[0015] For the purposes of the present invention, the expression“pseudo-azeotropic mixture” means a mixture of two constituents whoseboiling point (at a given pressure) differs from the boiling point ofthe true azeotrope by a maximum of 0.5° C. Mixtures whose boiling pointdiffers from the boiling point of the true azeotrope by a maximum of0.2° C. are preferred. Mixtures whose boiling point differs from theboiling point of the true azeotrope by a maximum of 0.1° C. areparticularly preferred.

[0016] 1,1,1,3,3-Pentafluorobutane and perfluoropentane form a binaryazeotrope or pseudo-azeotrope when their mixture contains from 50 to 87%by weight approximately of perfluoropentane. Binary compositionscontaining from 50 to 70% by weight approximately of perfluoropentaneare preferred. Binary compositions containing from 50 to 60% by weightapproximately are particularly preferred. Binary compositions containingfrom 65 to 80% by weight approximately of perfluoropentane are alsopreferred. Binary compositions containing from 70 to 78% by weightapproximately are particularly preferred. At a pressure of 100.1±0.2kPa, the binary composition consisting essentially of about 26% byweight of 1,1,1,3,3-pentafluorobutane and about 74% by weight ofperfluoropentane constitutes a true azeotrope whose boiling point isabout 24.4° C.

[0017] 1,1,1,3,3-Pentafluorobutane and perfluorohexane form a binaryazeotrope or pseudo-azeotrope when their mixture contains from 20 to 60%by weight approximately of perfluorohexane. Binary compositionscontaining from 25 to 45% by weight approximately of perfluorohexane arepreferred. Binary compositions containing from 32 to 42% by weightapproximately of perfluorohexane are particularly preferred. Binarycompositions containing from 35 to 40% by weight approximately ofperfluorohexane are most particularly preferred. At a pressure of101.2±0.5 kPa, the binary composition consisting essentially of about64% by weight of 1,1,1,3,3-pentafluorobutane and about 36% by weight ofperfluorohexane constitutes a true azeotrope whose boiling point isabout 36.4° C. This composition is most particularly preferred.

[0018] The invention also relates to compositions comprising1,1,1,3,3-pentafluorobutane, at least one non-flammable fluoro compoundand at least one non-fluoro organic solvent. The non-flammable fluorocompounds mentioned above are preferred as non-flammable fluorocompounds.

[0019] Non-fluoro organic solvents which are suitable for use, forexample, are hydrocarbons, chlorohydrocarbons, alcohols, esters, ketonesor ethers.

[0020] The hydrocarbons which can be used in the compositions accordingto the invention may be linear, branched or cyclic and generallycontain. 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms. Hydrocarbonscomprising at least 5 carbon atoms are suitable for use. Thehydrocarbons preferably comprise at least 6 carbon atoms. Among thealkanes or alkenes, compounds comprising from 5 to 12 carbon atoms arepreferred. n-Hexane, n-heptane and n-octane are suitable for use. Amongthe aromatic hydrocarbons which are preferred are those comprising atleast one alkyl substituent on a benzene ring. Toluene, 1,2-xylene,1,3-xylene, 1,4-xylene or mixtures thereof are most particularlypreferred.

[0021] The chlorohydrocarbons which can be used in the compositionsaccording to the invention may be linear, branched or cyclic andgenerally contain 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms.Chlorohydrocarbons comprising 1, 2, 3 or 4 carbon atoms are suitable foruse. The chlorohydrocarbons preferably comprise 1 or 2 carbon atoms.Among the chloroalkanes, dichloromethane, trichloromethane and1,2-dichloroethane are preferred. Among the chloroalkenes,perchloroethylene and 1,2-dichloroethylene are preferred.trans-1,2-Dichloroethylene is most particularly preferred.

[0022] 1,2-Dichloroethylene has the property of forming azeotropic orpseudoazeotropic mixtures with 1,1,1,3,3-pentafluorobutane, which canhave advantages for certain applications. Azeotropic orpseudo-azeotropic mixtures as well as ternary azeotropic orpseudo-azeotropic mixtures also comprising an alkanol are described inU.S. Pat. No. 5,478,492 in the name of the Applicant, the content ofwhich is incorporated by reference into the present patent application.

[0023] The alcohols which can be used in the compositions according tothe invention may be linear, branched or cyclic and generally contain 1,2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Alcohols comprising 1, 2, 3,4 or 5 carbon atoms are suitable for use. The alcohols preferablycomprise 1, 2, 3 or 4 carbon atoms. Among the alkanols, methanol,ethanol, n-propanol, isopropanol, n-butanol, isobutanol and tert-butanolare preferred. Methanol, ethanol, isopropanol and isobutanol give goodresults. Isobutanol is most particularly preferred.

[0024] Methanol has the property of forming azeotropic orpseudo-azeotropic mixtures with 1,1,1,3,3-pentafluorobutane, which canhave advantages for certain applications. The azeotropic orpseudo-azeotropic mixtures contain from 93 to 99% by weight of1,1,1,3,3-pentafluorobutane and from 1 to 7% of methanol. The trueazeotrope contains about 96.2% by weight of 1,1,1,3,3-pentafluorobutaneand about 3.8% by weight of methanol.

[0025] Ethanol has the property of forming azeotropic orpseudo-azeotropic mixtures with 1,1,1,3,3-pentafluorobutane, which canhave advantages for certain applications. The azeotropic orpseudo-azeotropic mixtures are described in U.S. Pat. No. 5,445,757 inthe name of the Applicant, the content of which is incorporated byreference into the present patent application.

[0026] The esters which can be used in the compositions according to theinvention can be linear, branched or cyclic and generally contain 3, 4,5, 6, 7, 8, 9 or 10 carbon atoms. Esters comprising 4, 5, 6, 7, 8 or 9carbon atoms are suitable for use. Preferably, the esters arederivatives of a carboxylic acid comprising at least 2 carbon atoms.Preferably, the esters are derivatives of an alkanol, selected from thegroup consisting of methanol, ethanol, n-propanol, isopropanol,n-butanol, isobutanol and tert-butanol. Ethyl acetate, ethyl butyrateand ethyl caproate are suitable for use.

[0027] The ketones which can be used in the compositions according tothe invention can be linear, branched or cyclic and generally contain 3,4, 5, 6, 7, 8, 9 or 10 carbon atoms. Ketones comprising 3, 4, 5, 6, 7 or8 carbon atoms are suitable for use. Among the ketones, acetone,2-butanone, 2- or 3-pentanone, methyl isobutyl ketone, diisopropylketone, cyclohexanone and acetophenone are preferred. Methyl isobutylketone is particularly preferred.

[0028] The ethers which can be used in the compositions according to theinvention can be linear, branched or cyclic and generally contain 2, 3,4, 5, 6, 7, 8, 9 or 10 carbon atoms. Ethers comprising 4, 5, 6, 7, 8 or9 carbon atoms are suitable for use. Among the aliphatic or alicyclicethers, diethyl ether, methyl isopropyl ether, diethylene glycolmonomethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and1,4-dioxane are preferred.

[0029] It has been found that the compositions according to theinvention comprising at least one non-fluoro organic solvent areparticularly suitable for applications as solvents for drying ordegreasing. The term “solvent for drying” refers to applications inwhich the compositions according to the invention are used to remove thewater present at the surface of solid articles. Specifically, it ispossible to achieve a wide variety of polarities of different solventswhile at the same time conserving the advantages as regards thenon-flammability of the compositions. Most particularly, thesecompositions make it possible to achieve good properties ofsolubilization of surfactants required, for example, for solvents fordrying.

[0030] Flammable or non-flammable solvents can be used. In the case of aflammable solvent, it is preferred to use a solvent which has a flashpoint of greater than or equal to 0° C. More particularly, a flash pointof greater than or equal to 10° C. is preferred. Solvents with a flashpoint of greater than or equal to 20° C. are most particularlypreferred.

[0031] In the case of a flammable non-fluoro organic solvent, aneffective amount of non-flammable fluoro compound is preferably used soas to obtain a non-flammable composition according to the invention.

[0032] For non-flammable non-fluoro solvents, the boiling point at 101.3kPa is not critical. Generally, the non-flammable solvents have aboiling point at 101.3 kPa of greater than or equal to 15° C.Preferably, the boiling point is greater than or equal to 20° C.Generally, the boiling point is less than or equal to 250° C. at 101.3kPa. Usually, the boiling point is less than or equal to 200° C.

[0033] When a flammable non-fluoro organic solvent is used, a solventwith a boiling point of greater than or equal to 30° C. is generallyused. Usually, the boiling point is greater than or equal to 40° C.Preferably, the boiling point is greater than or equal to 50° C. In aparticularly preferred manner, the boiling point is greater than orequal to 60° C. The reason for this is that this avoids an enrichment offlammable non-fluoro organic solvent in the gas phase and consequentlyavoids the formation of flammable gaseous mixtures.

[0034] According to the intended application, a non-fluoro organicsolvent which is miscible or immiscible with water can be used. Solventswhich are essentially immiscible with water are suitable, for example,for a drying application.

[0035] The amount of non-fluoro organic solvent in a compositionaccording to the invention comprising 1,1,1,3,3-pentafluorobutane, atleast one non-flammable fluoro compound and at least one non-fluoroorganic solvent can be chosen as a function of the desired polarity andflammability of the composition. Generally, this content is not morethan 20% by weight. Preferably, it is not more than 10% by weight. Whena non-fluoro organic solvent is present, its content is generally atleast 1% by weight. Preferably, it is at least 2% by weight.

[0036] The compositions according to the invention optionally contain asurfactant. Any surfactant which is well known per se and which iscompatible with the compositions according to the invention can be used.Advantageously, the surfactant is used with compositions according tothe invention comprising at least one non-fluoro organic solvent, asdescribed above. The reason for this is that these compositions areparticularly suitable for achieving a good solubility of the surfactantwhile at the same time retaining good properties as regards thenon-flammability of the compositions.

[0037] A number of surfactants which can be used in the compositionsaccording to the invention are described, for example, in Ullmann'sEncyclopedia of Industrial Chemistry, 5^(th) edition, 1987, vol. A8, pp.338-350. Cationic, anionic, nonionic and amphoteric surfactants can beused. It is possible, for example, to use fatty acids, fatty esters,alkylbenzenesulphonates, alkanesulphonates, α-olefin sulphonates,α-sulphonated fatty acid esters (SES), alkyl sulphates, alkyl ethersulphates, quaternary ammonium compounds, polyethylene glycol alkylethers, polyethylene glycol phenyl ethers, fatty acid alkanolamides,polyglycol fatty alkyl ethers, ethylene oxide and propylene oxide blockcopolymers, alkylbetaines, alkylsulphobetaines, tetraalkylammonium saltsof mono- or dialkylphosphoric acids or surfactants comprising at leastone imidazoline group. It is also possible to use surfactants such asthose described above containing at least one fluorine substituent. Morespecifically, surfactants comprising at least one polyfluoro alkyl chainor a polyfluoro aromatic substituent can be used.

[0038] In compositions according to the invention which can be used, inparticular, as drying agents, a surfactant of imidazoline type ispreferably used. In a particularly preferred manner, the imidazolinecorresponds to the formula:

[0039] in which R represents an alkyl or alkenyl chain comprising from 2to 25 carbon atoms, Y represents a hydroxyl or amino group and x is aninteger from 1 to 20. Preferably, x is from 1 to 12. Preferably, thechain R comprises from 10 to 20 carbon atoms. The imidazolines in whichR represents a chain comprising 11 or 17 carbon atoms and x is equal to2 are most particularly preferred.

[0040] The imidazoline can be in the form of the free base or in theform of a salt, preferably the mono- or dicarboxylate. The carboxylatepart is preferably derived from a saturated or unsaturated fatty acidcomprising from 4 to 22 carbon atoms. It is preferred to use theimidazoline in free form or in the form of the monocarboxylate salt.

[0041] A surfactant of alkylbenzenesulphonate type is also particularlypreferred. This surfactant often comprises an alkyl chain comprisingfrom 4 to 22 and preferably from 10 to 14 carbon atoms.Dodecylbenzenesulphonate salts, in particular the salts of a quaternaryamine, give good results. Isopropylammonium dodecylbenzenesulphonate isparticularly preferred.

[0042] When a surfactant is present in a composition according to theinvention, its content is generally at least 100 ppm (mg/kg). It isoften at least 500 ppm. Preferably, it is at least 1000 ppm. Generally,the surfactant content is not more than 5000 ppm. It is often not morethan 4000 ppm. Preferably, it is not more than 3000 ppm. When asurfactant of imidazoline type as described above is used, itsparticularly preferred content is about 2000 ppm. The table belowcollates, in a non-limiting manner, a number of preferred compositionsaccording to the invention. TABLE 1 Content of Content of Content ofContent of Non-fluoro HFC-365mfc perfluorohexane HFC-43-10mee HFE-7100organic solvent No. (% by weight) (% by weight) (% by weight) (% byweight) (% by weight) 1 30-60 — 40-70 — — 2 15-45 — — 55-85 — 3 30-4949-60 — — ethyl acetate 2-10 4 30-49 — 49-60 — ethyl acetate 2-10 525-38 — — 60-68 isopropanol 2-5  6 55-63 35-45 — — ethyl acetate 2-10 740-50 — — 50-60 —

[0043] The compositions according to the invention can be used, forexample, is solvent applications, as drying agents, as degreasingsolvents or as toner-fixing agents. The compositions according to theinvention can also be used as refrigerants or heat-exchange fluids.

[0044] A drying agent is used, for example, in the electronics orelectro-mechanical industry or optionally the cosmetic industry when itis desired to remove the water adsorbed onto a solid surface of anobject after an aqueous treatment. The aqueous treatment can consist,for example, of a cleaning operation, optionally in the presence of asurfactant. Generally, after the aqueous treatment, the object isimmersed in a drying agent in the boiling state comprising a surfactant,and the surfactant which adheres to the surface of the object is thenremoved in a washing bath. The compositions according to the inventioncomprising a surfactant are suitable for the drying operation. Thecompositions according to the invention which are free of surfactant aresuitable for the washing bath intended to remove the surfactant.

[0045] A degreasing solvent is used, for example, in the electronics orelectromechanical industry to remove the grease adsorbed in particularonto metal components machined with grease. Generally, a component to bedegreased is immersed in a bath of boiling degreasing solvent. Thecompositions according to the invention comprising a non-fluoro organicsolvent of high polarity, such as alkanols, in particular methanol orethanol and/or those which comprise a chlorohydrocarbon, areparticularly suitable as degreasing solvents.

[0046] A toner-fixing agent serves to fix toner particles onto asupport. Toner particles generally comprise a polymer and a pigment.During an electrophotographic printing operation, the particles areattracted to the electrostatic image printed on the support byelectrostatic forces. The toner-fixing agent serves to soften thepolymer which consequently ensures permanent adhesion of the particlesonto the support. The toner-fixing agent is used in the form of vapours,usually generated by vapourizing drops of solvent on a heating plate,for example. The non-flammable compositions according to the inventionwhich have good polymer-solvent power are particularly suitable for thisapplication.

[0047] The non-flammable compositions according to the invention can beused advantageously as drying agents in a drying machine or astoner-fixing agents in an industrial laser printer.

[0048] The compositions according to the invention are also suitable asrefrigerant fluids, in particular as products to replace CFC-11(trichlorofluoromethane) or as products to replace CFC-113(1,1,2-trichlorotrifluoroethane), in particular for applications with aturbocompressor. Turbocompressors are especially used when it is desiredto have available large refrigeration productions for air-conditioninginstallations, for example, or for the processing industry. Informationregarding the applications in refrigeration, heat-exchange fluid andrefrigeration with a turbocompressor is contained, for example, inUllmann's Encyclopedia of Industrial Chemistry, 5^(th) edition, 1988,vol. B3, pp. 19-2 to 19-39. Compositions consisting essentially of1,1,1,3,3-pentafluorobutane and of one or more non-flammable fluorocompounds selected from perfluorohexane, perfluoropentane andperfluorobutyl methyl ether, especially if these compositions areazeotropic or pseudo-azeotropic, are particularly suitable for thisapplication.

[0049] The compositions according to the invention comprising1,1,1,3,3-pentafluorobutane and perfluoropentane, in particular thosecontaining or consisting of from 10 to 90% by weight of HFC-365mfc andfrom 90 to 10% by weight of perfluoropentane, are suitable for use asproducts to replace CFC-11 in applications as refrigerants orheat-exchange fluids. A preferred composition for this applicationconsists of from 25 to 30% by weight of HFC-365mfc and from 75 to 70% byweight of perfluoropentane. A composition containing from 27.0 to 27.2%by weight of 1,1,1,3,3-pentafluorobutane and from 72.8 to 73.0% ofperfluoropentane is most particularly preferred.

[0050] The compositions according to the invention comprising1,1,1,3,3-pentafluorobutane and perfluorohexane, in particular thosecontaining or consisting of from 10 to 90% by weight of HFC-365mfc andfrom 90 to 10% by weight of perfluorohexane; those comprising1,1,1,3,3-pentafluorobutane and perfluorobutyl methyl ether, inparticular those containing or consisting of from 10 to 90% by weight ofHFC-365mfc and from 90 to 10% by weight of perfluorobutyl methyl ether;and those comprising 1,1,1,3,3-pentafluorobutane, perfluorohexane andperfluorobutyl methyl ether, are suitable for use as products to replaceCFC-113 in applications as refrigerants or heat-exchange fluids. Apreferred composition for this application consists of from 60 to 65% byweight of HFC-365mfc and from 40 to 35% by weight of perfluorohexane. Acomposition containing from 61.0 to 62.0% by weight of1,1,1,3,3-pentafluorobutane and from 38.0 to 39.0% of perfluorohexaneare particularly suitable for this application. Another preferredcomposition for this application consists of from 40 to 60% by weight ofHFC-365mfc and from 60 to 40% by weight of perfluorobutyl methyl ether.

[0051] The examples given below are intended to illustrate the inventionwithout, however, limiting it.

EXAMPLES 1 AND 2

[0052] HFC-365mfc/perfluorohexane and HFC-365mfc/perfluoropentaneazeotropes

[0053] In order to demonstrate the existence of azeotropic orpseudoazeotropic compositions according to the invention between1,1,1,3,3-pentafluorobutane and perfluoropentane or perfluorohexane,glass apparatus consisting of a 50-ml boiling flask with a refluxcondenser mounted on top was used. The temperature of the liquid wasmeasured by means of a thermometer dipping into the flask.

[0054] An accurately determined amount of pure1,1,1,3,3-pentafluorobutane was heated to the boiling point at a knownpressure, and accurately weighed small amounts of perfluorocarbon weregradually introduced into the flask by means of a syringe, via a sidetube.

[0055] The determination of the pseudo-azeotropic compositions wascarried out by reading the change in boiling point of the mixture as afunction of its composition.

[0056] These measurements were carried out for mixtures containing1,1,1,3,3-pentafluorobutane and increasing amounts of perfluorohexane(Example 1) or of perfluoropentane (Example 2).

[0057] The pressure at which the measurements were taken is given. Thechange in boiling point of the various compositions as a function oftheir perfluorocarbon content, expressed as a % by weight, is given inTable 2. TABLE 2 Pressure: 100.1 ± 0.2 kPa HFC-365mfc PerfluoropentanePF5050 Temperature % by weight % by weight ° C. 100.00% 0.00% 39.893.77% 6.23% 34 91.93% 8.07% 32.2 90.05% 9.95% 31 88.20% 11.80% 3086.40% 13.60% 29.6 83.54% 16.46% 29 80.75% 19.25% 28.4 78.14% 21.86% 2874.70% 25.30% 27.6 71.38% 28.62% 27.2 67.70% 32.30% 26.6 62.95% 37.05%26 57.25% 42.75% 25.6 52.57% 47.43% 25.2 50.63% 49.37% 25.2 45.07%54.93% 25 40.19% 59.81% 24.8 38.46% 61.54% 24.6 31.07% 68.93% 24.425.99% 74.01% 24.4 22.92% 77.08% 24.4 20.18% 79.82% 24.4 17.61% 82.39%24.8 15.44% 84.56% 24.8 13.28% 86.72% 24.8 11.31% 88.69% 25.2 9.41%90.59% 25.8 7.31% 92.69% 26.4 5.28% 94.72% 27.4 3.49% 96.51% 28.4 2.45%97.55% 29.2 0.00% 100.00% 29.6

[0058] TABLE 3 Pressure: 101.2 ± 0.5 kPa HFC-365mfc PerfluorohexanePF5060 Temperature % by weight % by weight ° C. 100.00% 0.00% 40 94.61%5.39% 38.8 93.31% 6.69% 38.6 91.81% 8.19% 38.4 90.23% 9.77% 38 88.33%11.67% 37.8 86.06% 13.94% 37.6 83.69% 16.31% 37.4 80.81% 19.19% 3776.52% 23.48% 36.8 71.60% 28.40% 36.6 66.96% 33.04% 36.4 60.88% 39.12%36.4 53.48% 46.52% 36.4 47.09% 52.91% 36.6 43.65% 56.35% 37 42.05%57.95% 36.8 36.42% 63.58% 37.6 29.55% 70.45% 38.2 26.12% 73.88% 38.823.01% 76.99% 39.2 20.59% 79.41% 39.8 18.56% 81.44% 40.4 16.61% 83.39%41.2 14.77% 85.23% 42.4 13.09% 86.91% 43.6 11.43% 88.57% 44.4 9.80%90.20% 45.6 8.43% 91.57% 46.8 7.18% 92.82% 48 5.90% 94.10% 49.6 4.63%95.37% 51.2 3.44% 96.56% 53.2 2.32% 97.68% 54.4 1.16% 98.84% 56.4 0.00%100.00% 57.2

[0059] The azeotropic or pseudo-azeotropic mixturesHFC-365mfc/perfluorohexane or HFC-365mfc/perfluoropentane arenon-flammable.

EXAMPLE 3

[0060] A composition according to the invention containing 50 parts byweight of HFC-365mfc, 50parts by weight of perfluorohexane PF-5060 and10 parts by weight of ethyl acetate was prepared. The composition washomogeneous. It was subjected to the test according to ISO standard1523. The composition showed no flash point.

EXAMPLE 4

[0061] A composition according to the invention containing 40 parts byweight of HFC-365mfc, 60 parts by weight of perfluorobutyl etherHFE-7100 and 5 parts by weight of isopropanol was subjected to the testaccording to ISO standard 1523. The composition showed no flash point.

EXAMPLE 5

[0062] Solubility of the surfactant Imidazoline18NH(N-(2-aminoethyl)-2-n-octadecylimidazoline) in ternary mixtures.

[0063] 0.026 g of Imidazoline 18NH was dissolved in 2 g of xylene(technical-grade mixture of isomers) and 20 g of a mixture containing 13g of HFC-365mfc and 7 g of perfluorohexane were added. The homogeneoussolution obtained contains 1182 ppm of Imidazoline 18NH. This solutionwas subjected to a rapid flammability test by attempting to ignite thesolution at room temperature using a match. The solution did not ignite.

EXAMPLE 6

[0064] The process was performed as in Example 5, replacing the xylenewith the same amount of toluene. The homogeneous solution obtainedcontains 1182 ppm of Imidazoline 18NH. The solution did not ignite inthe test described in Example 5.

EXAMPLE 7

[0065] 0.022 g of Imidazoline 18NH was dissolved in 1 g of isobutanoland 20 g of a mixture containing 13 g of HFC-365mfc and 7 g ofperfluorohexane were added. The homogeneous solution obtained contains1048 ppm of Imidazoline 18NH. The solution did not ignite in the testdescribed in Example 5.

EXAMPLE 8

[0066] A PVDF plate of rectilinear geometry with a height of 10 cm, awidth of 2 cm and a thickness of 1 cm pierced through its thickness with20 holes 2 mm in diameter was immersed in water in order to block allthe holes.

[0067] The plate was dipped for 15 seconds into a drying solution in theboiling state, containing HFC-365mfc (65 parts by weight),perfluorohexane PF-5060 (35 parts by weight), isobutanol (5 parts byweight) and 1610 ppm of Imidazoline 18NH obtained in a similar manner tothat of Example 5. The plate was removed and dried in air for 2 minutes.The dipping/drying operation was repeated 4 times, corresponding to atotal dipping time of 60 seconds. At the end of this treatment, all theholes were free of water.

EXAMPLE 9

[0068] The process was performed as in Example 8, using a dryingsolution containing 40 parts by weight of HFC365mfc, 60 parts by weightof perfluorobutyl ether HFE-7100, 5 parts by weight of isobutanol and2000 ppm of Imidazoline 18NH. After a total dipping time of 60 seconds,19 of the 20 holes were free of water.

EXAMPLE 10

[0069] The process was performed as in Example 8, using a dryingsolution containing 36.4 parts by weight of HFC365mfc, 54.5 parts byweight of perfluorobutyl ether HFE-7100, 9.1 parts by weight ofisobutanol and 2500 ppm of isopropylammonium dodecylbenzenesulphonate.After a total dipping time of 60 seconds, all the holes were free ofwater.

1-11. Cancelled.
 12. A composition comprising 1,1,1,3,3-pentafluorobutane and more than 5% of weight of at least one non-flammable fluoro compound presenting no flash point according to ISO standard 1523, selected from perfluorocarbons and fluoroamines.
 13. The composition according to claim 12, further comprising at least one non-fluoro organic solvent.
 14. The composition according to claim 13, in which the non-fluoro organic solvent is a hydrocarbon, halohydrocarbon, aliphatic ester, aromatic ester, ketone, alcohol or ether.
 15. The composition according to claim 14, in which the non-fluoro organic solvent is ethyl acetate, 1,2-dichloroethylene, methanol, ethanol, isopropanol or isobutanol.
 16. The composition according to claim 13, comprising 1,1,1,3,3-pentafluorobutane and the non-fluoro organic solvent in proportions in which they form an azeotrope or a pseudo-azeotrope.
 17. The composition according to claim 12, further comprising a surfactant.
 18. The composition according to claim 17, wherein said surfactant is an imidazoline or alkylbenzenesulphonate type.
 19. The composition according to claim 12, wherein said nonflammable fluoro compound is perfluorotriethylamine, perfluoropentane or perfluorohexane.
 20. The composition according to claim 12, comprising 1,1,1,3,3-pentafluorobutane and at least one perfluorocarbon in proportions in which they form an azeotrope or a pseudo-azeotrope.
 21. The composition according to claim 20, comprising a) an azeotropic or pseudo-azeotropic mixture consisting essentially of from 40 to 80% by weight of 1,1,1,3,3-pentafluorobutane and from 20 to 60% by weight of perfluorohexane, or b) an azeotropic or pseudo-azeotropic mixture consisting essentially of from 13 to 50% by weight of 1,1,1,3,3-pentafluorobutane and from 50 to 87% by weight of perfluoropentane.
 22. A method selected from a method involving use of a solvent, a method for drying, a method for degreasing, a method for fixing a toner, a method for refrigerating, a method for exchanging heat, which comprises using the composition according to claim
 12. 23. The method according to claim 22, wherein the composition is used as a product to replace a chlorofluorocarbon selected from CFC-11 (trichlorofluoromethane) and CFC-113 (1,1,2-trichlorofluoroethane).
 24. A solvent which comprises the composition according to claim
 12. 25. A degreasing solvent which comprises the composition according to claim
 12. 26. A drying agent which comprises the composition according to claim
 12. 27. A toner-fixing agent which comprises the composition according to claim
 12. 28. A refrigerant which comprises the composition according to claim
 12. 29. A heat exchange fluid which comprises the composition according to claim
 12. 30. A composition according to claim 12, which comprises an effective amount of non-flammable fluoro compound which makes the composition non-flammable.
 31. A composition according to claim 12, wherein the number of fluorine atoms divided by the number of hydrogen atoms in the molecule of the nonflammable fluoro compound is greater than
 2. 32. A composition according to claim 12, wherein the non-flammable fluoro compound comprises a perfluorocarbon.
 33. A composition according to claim 32, wherein said perfluorocarbon is perfluoropentane.
 34. A composition according to claim 32, wherein is said perfluorocarbon perfluorohexane. 